Salt spray is used for accelerated corrosion testing that is used to assess the relative corrosion resistance of certain materials when exposed to salt spray or salt spray at specific temperatures.
In this test, the sample is placed indoors or in a cabinet for a salt spray test, in addition to keeping the climate unchanged during the test. We will continue to spray salt water mist or indirect fog. So salt spray test is also called the fog test or salt spray test.
In fact, salt spray test chambers can be used by almost any company that produces products exposed to corrosive environments. Includes a large number of companies in the automotive, defense, consumer goods, telecommunications, paints, and polymers sectors. And the list continues to grow.
Usually, a salt spray chamber is used to perform various salt spray and corrosion tests. The testing time can range from a few hours to several months. This helps determine if your product will survive the corrosive conditions to which it is exposed. Furthermore, this type of testing can also be used to determine which part of your product is likely to fail first. And in some cases, can help you determine the actual use of the product.
Linkotest designs and manufactures environment test chambers including temperature humidity chambers, walk-in test chambers, thermal shock test chambers, fast change rate test chambers, agree chambers, xenon arc test chambers, uv test chambers, accelerated aging test chambers, rain & spray test chamber, salt spray test chamber, compound salt spray test chamber, laboratory oven, and other products to meet your different environmental test needs.
Although it is known as the salt spray test and the salt spray test chamber, the name is somewhat misleading. Because the spray usually comes in the form of fog or ultra-fine fog, to create an environment that accelerates corrosion. On the other hand, this condition can also be isolated by controlling the ambient temperature at 95°F(35°C) and PH.
Salt spray testing is used to determine the corrosion resistance of a material. These typically include the following:
- Phosphating the surface followed by paint, primer, varnish, or anti-rust treatment
- Galvanized and zinc alloys
- Electroplated chrome, nickel, copper, and tin
- Coatings that are not electrolyzed, such as zinc sheet coatings
- Organic coatings
- Paints and coatings
Corrosion is the destruction or deterioration of a material or its properties caused by the environment. According to the survey, most corrosion occurs in the atmosphere, which contains corrosive components and corrosion factors such as oxygen, humidity, temperature changes, and pollutants. Therefore, salt spray detection products are very important.
In fact, salt spray corrosion is one of the most common and destructive forms of atmospheric corrosion. The corrosion of the surface of the metal material by salt spray is caused by the electrochemical reaction of the penetrating metal surface and protective layer with the chloride layer of the internal metal.
By comparing the artificially simulated salt spray environmental test and the natural environment, we found that the concentration of chloride in the artificial simulated salt spray environment can be several times or several times the salt content of the general natural environment.
Therefore, artificially stimulated salt spray environmental tests greatly increase the corrosion rate. In addition, it can reduce the time to obtain results. If your product samples are tested in a naturally exposed environment. This can take up to 1 year to corrode. However, in an artificially simulated salt spray environment, you can get similar results in just 24 hours.
Likewise, the salt spray test chamber not only helps you evaluate the quality of the metal but also provides you with a complete analysis of the durability of the metal coating when exposed to saline environments. Therefore, with this laboratory test equipment, you can easily perform a comprehensive analysis of the durability of metals.
- The Salt Spray Test Chamber is one of the highly advanced test instruments that will help you test the durability of your metal products.
- The PVC model of this laboratory test instrument will help you to detect the quality of materials under different environmental conditions.
- It has a three-walled structure that helps you limit moisture or any contaminants in the test room.
- It will accurately test the effect of corrosion on the product within a few test hours.
There are many unique features of a salt spray test chamber compared to other testing machines. They mainly include:
- Integrated immersion heater for condensing humidity for testing a wider range of “modified” salt spray tests.
- The intuitive 7-inch touchscreen, full-color user control interface, and the latest version of our highly intuitive operating software are easy to program and use.
- The operating software has a very large capacity and can be used to create complex multi-step test programs, so it can accommodate the widest possible test profile.
- The icon-based control interface provides several built-in languages for ease of understanding and use.
- The RJ45 communication port enables the chamber to be connected to a local area network (LAN) via wired or wireless for recording and remote programming from a computer running optional software.
- A real-time, user-configurable “clock” that batches different test samples and monitors their exposure time individually, alerting them when a preset test cycle is complete.
- Touch screen operator control interface.
- ”Easy to open” pneumatically operated canopy.
- Dry sealing gaskets prevent getting the operator’s clothes wet, for example.
- Low load thresholds for loading and unloading.
- Large capacity floor-standing salt solution reservoir.
- Calibration certificate.
- Canopy color selection.
- One set of sample holders.
- Interior picture windows.
- Consumable spare parts kit.
- Easy-to-access salt mist nebulizer made of transparent, wear-resistant acrylic.
- Purges the cabinet interior with fresh air after testing and before opening the chamber.
- Touch screen, full-color user control interface, the latest version of our highly intuitive operating software, easy to program and use.
- The operating software has a very large capacity and can be used to create complex multi-step test programs, so it can accommodate the widest possible test profile.
Next, I will show you how to use a salt spray test chamber.
1) First, the salt spray test pool water supply system installation
- Water quality requirements: filter industrial water or tap water. The pH of the filtered water is the salt spray corrosion cabinet.
- Pressure requirements: water pressure is 1 ~ 3 kg, to ensure normal water supply.
- Interface requirements: The water supply outlet of the equipment should be connected by a hose and fixed with a sealing ring to prevent leakage.
2) Second, salt spray test chamber power supply system requirements
- Power requirements: single-phase AC 220V 50Hz
- Current requirement: maximum 15 A
- Protection requirements: it is necessary to install an independent leakage protection switch
3) Third, the salt spray test chamber intake system installation
- Pressure requirements: air compressor or supply air pipeline pressure ≥ 3 kg, and dry and clean.
- Interface requirements: The equipment adopts a quick connector, which is easy to disassemble and maintain.
- Time requirements: During the normal operation of the equipment, the test equipment must be provided uninterrupted for a long time.
4) Fourth, salt spray test chamber exhaust system requirements
- Material requirements: PVC polyethylene material must be used (corrosion resistant)
- Interface requirements: the equipment exhaust port should be connected by a hard pipe and sealed with a sealant to prevent air leakage.
5) Fifth, salt spray corrosion test chamber drainage system installation
- Drilling requirements: the natural drainage of the equipment is pressureless, and the height of the wall opening should be lower than the drainage outlet to ensure that the drainage work is normal.
- Interface requirements: The salt spray test chamber outlet should be connected with a hose or hard pipe and fixed with a sealing ring to prevent leakage.
6) Operational points
- First, you need to connect the salt spray chamber power supply to the air compressor power supply. And connect the air pressure pipe.
- You will need to add purified or distilled water to the inlet in the cabinet and behind the cabinet. It will not work properly until the low water level on the panel is closed.
- The connection between the drain pipe and the exhaust pipe is completed, and the indicator light is turned on to the left.
- Add water to the insulated can of the mat to prevent salt spray from leaking.
- Preparation method of test solution preparation method: According to the actual test requirements, prepare a matching solution for testing.
- Pour the brine into the salt filling bottle, that is, automatically pour the brine into the spray tower of the laboratory, so that the syrup flows to the salt spray tower.
- Add water to the wet bulb, cover the wet bulb thermometer with gauze, and put the end of the gauze into the wet bulb.
- Place the sample on a rack, set the test temperature and time, adjust the pressure-reducing valve, and then start the test.
7) Additional details you need to know
Here are some additional details you need to know.
#1. Salt spray chamber ventilation
To prevent back pressure in the chamber, you must exhaust it. When setting up the chamber, you are sure to install a non-corrosive three-inch pipe from the exhaust chamber to a point outside the building. It is worth noting that this exhaust port should be short and straight.
And gently slope down from the chamber to avoid any liquid traps. Finally, it should also shield the effects of wind or airflow. While flexible hoses are also an option, you must ensure that the hose does not sag. If it sags, it creates a liquid trap.
If your exhaust pipe is longer than 10 feet, a two-inch line should be used. If your pipe must exit from the roof up, use a T-joint instead of a bend. Finally, adjust the T so that an 18-inch drop line and drain pipe can be added to ensure that the exhaust line always remains clear.
#2. Salt chamber air supply
An important point is that the salt spray chamber needs clean, oil-free compressed air. In addition, install a valve labeled “air” at the back end of the salt spray chamber. Compressed air flow SCFM typically ranges from 1.5/0.71 (l/s) to 4.0/1.89. The pressure of the PSIG will run between 6-10, depending on the model.
Your salt mist chamber should now be fully set up. Read on to learn more about how to operate it.
In reality, there are many testing standards that define how a product should be tested. These standards are typically developed by a wide variety of manufacturers and testing laboratories and are then available to anyone designing similar products.
Here are some of the more common standards, such as ASTM B117 (B-117), ASTM G 85, and DIN EN ISO 9227. And a wide range of automotive and defense standards, including the Volvo STD 5711 and Mil-STD 202H.
Furthermore, modern salt spray test cabinets are capable of performing a variety of tests in a variety of temperature and humidity environments. And different salt solutions are used for different durations.
Definitely, a salt spray test is an important method to check the corrosion resistance of products or materials to salt spray. The scientific and reasonable results of the test are very important to you. However, there are many factors affecting the stability and consistency of salt spray test results. But the key to improving the validity of salt spray test results is the test technology.
Therefore, test operators need not only specialized knowledge and professional skills but also a wealth of practical experience and a comprehensive understanding of the product. The salt spray test is understood from chemical environmental engineering, materials, structure, technology, and other disciplines, and the test results can be expressed scientifically and reasonably.
To better provide effective information for your product selection, structural design, process selection, product transportation, storage, use, etc. Ultimately improve the corrosion resistance of the product or material
·Easy to maintain and long-term use
·Easy-to-use test setup
·Easy to install in any location
·Simple structure, simple setup
According to the survey, the finer the salt spray particles, the greater the surface area formed. The more oxygen adsorbed, the more corrosive it is. In general, the traditional spraying methods include the gas spraying method and the spray tower method. However, the most obvious disadvantages are the poor uniformity of the salt spray test method and the large diameter of the salt spray particles. Therefore, different spray methods also have an effect on the pH value of the salt solution.
Generally, salt spray tests fall into two broad categories. The first is the natural environmental exposure test, and the other is the artificial accelerated simulated salt spray environmental test. Artificial simulated salt spray environment test adopts the test equipment with a certain volume space salt spray test chamber.
The salt spray environment in the volume space is used to evaluate the corrosion resistance of the product. Compared to the natural environment, the salt concentration of chloride in the salt spray environment can be several times or several times the salt spray content of the general natural environment. This allows the corrosion rate to be greatly increased, and the product can be tested through the salt spray test chamber to obtain results.
This can greatly reduce your time. If your product sample is tested in a naturally exposed environment, it may take up to 1 year to corrode. However, in a simulated salt spray environment, you can get similar results in just 24 hours.
What’s more, the artificial simulated salt spray test includes a neutral salt spray test chamber, acetate spray test, copper salt accelerated acetate spray test, and alternating salt spray test.
In fact, the critical relative humidity for metal corrosion is about 70%. When the relative humidity reaches or exceeds this critical humidity, the salt dissolves to form an electrolyte with good electrical conductivity. Conversely, when the relative humidity decreases, the salt solution concentration increases.
Until the crystallization salt is out, the corrosion rate decreases accordingly. In addition, when the temperature increases, the molecular movement is intensified, and the salt spray corrosion rate is high. The International Electrotechnical Commission pointed out that for every 10℃ increase in temperature, the corrosion rate is increased by 2 to 3 times.
And the conductivity of the electrolyte is increased by 10 ~ 20%. For a neutral salt spray test, it is generally considered appropriate to choose a 35℃ test temperature.
When the concentration is less than 5%, the corrosion rate of steel, nickel, and brass increases with the increase of the concentration. On the other hand, when the concentration exceeds 5%, the corrosion rate of these metals decreases with the increase in the concentration. This is because, in the low concentration range, the oxygen content increases with the salt concentration; When the salt concentration is increased to 5%, the oxygen content reaches relative saturation.
If the salt concentration continues to increase, the oxygen content decreases accordingly. With the decrease in oxygen content, the depolarization ability of oxygen also decreases, that is, the corrosion effect is weakened. In short, for zinc, cadmium, copper, and other metals, the corrosion rate always increases with the increase of the concentration of the salt solution
Whenever you deliver a product to a customer, it is important to test your product for quality. This will help cover all defects (if any) in the product. Therefore, you can test a metal sample in a salt spray chamber to test the corrosion of the surface.
- The salt spray test chamber is used to simulate the environment in which the ship is operating.
- Salt spray test chambers can be used to test surfaces for corrosion, wear, and erosion.
- Salt spray test chambers can also be used to study how different materials react with water under a variety of conditions.
- Mix the salt with the water in the chamber and spray it onto the surface of the device using a nebulizer.
- The chamber is filled with a mixture of water and air and sprayed at the bottom for testing.
- It may take several hours to obtain valid test results.
- The salt spray chamber can easily help improve product quality through several testing steps.
- The salt spray test chamber contains a triple wall that restricts the entry of moisture or any contaminants that may affect the test.
- The artificially created environment will be used to test the effectiveness of the sample in this environmental chamber.
- All materials that react with or are oxidized with oxygen can be easily tested using this test instrument.
- Regularly clean and maintain the pressure barrel, saltwater tank, and nozzle of the salt spray test chamber.
- Do not manually add water from the pressure tank, pour the sodium chloride solution into it. Before adding distilled water, clean the solution graduated cylinder.
- Do not block the rear exhaust pipe during the test, so as to avoid the deformation of the chamber due to excessive pressure in the chamber.
- Do not put inflammable and explosive materials into the chamber.
- The pressure gauge on the back of the salt spray test chamber is 2 kg and on the front is 1 kg.
- If the amount of spray is insufficient, raise the spray tower. If the spray volume is too large, please lower the spray tower (the standard for collecting the spray volume is 1 ~ 2ml /h, and the average value is 16 hours).
- The power supply is plugged in, so do not release the power supply.
- Confirm the automatic water and gas supply system.
- Keep the sink sealed and confirmed.
- Whether the ventilation hole is free and there is no foreign body.
- After the test, the power supply, gas source, and water source of the equipment should be cut off in time to prevent the equipment from being in standby mode.
We understand your need to ship their equipment quickly and in a timely manner. Delivery time usually varies from 15 to 45 days per day and is indicated in the quotations we give you. Be sure to discuss your more urgent requirements with your sales representative so that we can ensure that your expectations are met.
We can provide you with on-site training and provide installation and operation videos. You can follow the video or the instruction manual step by step. We also recommend that you ask an experienced local engineer to install the equipment for you according to our operation video. Because for experienced engineers, the installation process is very simple.